Abstract
The Massambaba Environmental Protection Area lies within the Cabo Frio Center of Plant Diversity, which has high species richness when compared to the entire Brazilian south-southeast coast. The restingas (sandy coastal plains) predominate in this region and they suffer from environmental stress plus historic manmade activities. This work aims to survey the floristic composition and structure of the herb layer of an open scrub formation in the Massambaba Environmental Protection Area, and compare it to a physionomically similar formation. The herb layer was sampled by the plot technique, totaling 200 m2. The parameters frequency, cover and Importance Value were calculated for each species. For the comparisons with the Clusia scrub formation (Macaé, RJ), similarity indices (Sorensen's qualitative and quantitative), diversity (Shannon) and evenness (Pielou) were used. A total of 33 species were recorded for the herb layer, showing an oligarchic structure with the following dominants: Panicum trinii, Allagoptera arenaria, Vriesea neoglutinosa, Chamaecrista ramosa, Sebastiania glandulosa, Couepia ovalifolia, Diodella apiculata and Cuphea flava. Jurubatiba's herb layer was very similar to Massambaba's (Cs=0.59); the latter has higher diversity (H'C=2.32 nats/m2).
Key words:
herb layer; phytosociology; sandy coastal plain; Rio de Janeiro